Often, it is necessary to deliver fluid to a fluid utilization device which is located in cramped quarters adjacent other structures that limit the amount of space available for a conduit. One location where this problem may be encountered is in jet aircraft that typically includes a relatively large number of components packed within a confined volume of space. In one particular aircraft installation, an inducer inlet of a jet engine fuel pump is located in close proximity to other engine components, thereby resulting in a limited amount of available space for delivering fuel to the fuel pump. In this installation, a conduit having a sharp bend of limited length along the axial direction of the fuel pump is required. Further, the cross-sectional area of an inlet of the conduit is specified as being a certain size smaller than the cross-sectional area of the inducer inlet of the fuel pump. Thus, fuel must diffuse as well as turn sharply before entering the pump. Typically, pumps utilizing this type of conduit suffer from reduced two-phase flow capability, cavitation on the walls of the inlet cavity, head loss and unsteady flow patterns.
Aarestad U.S. Pat. No. 4,880,352 discloses a centrifugal liquid pump having a housing section and an impeller section. The housing section includes an intake cavity having a ramp formed therein which imparts both an axial component of motion on liquid flowing through the housing toward the impeller section as well as a radial component of motion on the liquid inwardly toward a pump axis. The ramp insures contaminants in the liquid pass with the liquid inwardly and upwardly into the impeller section.
Yu U.S. Pat. No. 4,787,421 discloses flow paths for conducting fluids. Flow bodies such as a manifold passage, a turbine scroll casting and an elbow are described wherein the flow bodies are defined in accordance with a super-elliptical equation. Some of the flow bodies include cross-sectional areas of continuously decreasing cross-sectional size along the length of the body.
Other patents disclosing the use of flow passages include Demyan U.S. Pat. No. 3,191,630, Gluntz U.S. Pat. No. 3,404,296, Scott U.S. Pat. No. 4,098,251, Kobayashi, et al U.S. Pat. No. 4,280,360, Jinkins U.S. Pat. No. 4,281,964, Greco et al U.S. Pat. No. 4,536,139, Friedrichs U.S. Pat. No. 4,784,185 and Sukimoto et al U.S. Pat. No. 4,809,743.